Diffusion of nicotinic acid in spray-dried capsules of whey protein isolate. (January 2016)

• Record Type: Journal Article
• Authors: Panyoyai, Naksit; Bannikova, Anna; Small, Darryl M.; Shanks, Robert A.; Kasapis, Stefan
• Is Part Of: Food hydrocolloids. Volume 52(2016:Jan.)
• Page Start: 811
• Page End: 819
• Publication Date: 2016-01
• Subjects: Whey protein isolate -- Nicotinic acid -- Mechanical glass transition temperature -- Microencapsulation -- Diffusion coefficient; Hydrocolloids -- Periodicals; Food additives -- Periodicals; Colloïdes -- Périodiques; Aliments -- Additifs -- Périodiques; Colloids; Food additives; Periodicals; Electronic journals; 664.06
• DOI: 10.1016/j.foodhyd.2015.08.022
• Languages: English
• ISSNs: 0268-005X

Abstract

Abstract: Diffusion patterns of nicotinic acid were evaluated following its microencapsulation into a whey protein matrix through spray drying. Micro-differential scanning calorimetry, small-deformation rheological techniques, wide-angle X-ray scattering, Fourier transform infrared spectroscopy, particle size analysis and scanning electron microscopy were utilised to characterize encapsulant and bioactive compound in the composite material. UV–vis spectroscopy, the newly introduced concept of spectroscopic shift factor and the König reaction were also employed to elucidate the rate of vitamin transport throughout the polymeric matrix as a function of a broad time and temperature spectrum. Mechanical properties of the condensed matrix followed a progression that was described with the combined Williams-Landel-Ferry/free volume theory leading to the prediction of the mechanical glass transition temperature. Modified Arrhenius equation demonstrated that the kinetics of nicotinic-acid mobility were distinct from the structural relaxation of the polymeric segments. The former was further examined using the second law of Fickian diffusion. A direct relationship between fractional free volume of the whey protein network and diffusion coefficient of the nicotinic acid was established within the experimental temperature range. Graphical abstract: Highlights: The mechanism of nicotinic acid diffusion in whey protein capsules is studied. For the first time, free volume theory was combined with Fickian diffusion kinetics. Physics and the rate of nicotinic acid transport in whey protein capsules are elucidated.